DrIFT - a type sensitive preprocessor for Haskell

DrIFT [ options ... ] file ...

It extracts type declarations and directives from modules. The directives cause rules to be fired on the parsed type declarations, generating new code which is then appended to the bottom of the input file. The rules are expressed as Haskell code, and it is intended that the user can add new rules as required.

DrIFT automates instance derivation for classes that aren't supported by the standard compilers. In addition, instances can be produced in separate modules to that containing the type declaration. This allows instances to be derived for a type after the original module has been compiled. As a bonus, simple utility functions can also be produced from a type.

-v, --verbose

chatty output on stderr

-V, --version

show version number

-l, --list

list available derivations

-L, --noline

omit line pragmas from output

-o FILE, --output=FILE

output FILE

-s name:value, --set=name:value

set argument to value

-r, --results-only

output only results, do not include source file

-g rule, --global=rule

addition rules to apply globally

-i, --ignore

ignore directives in file, which is useful with -g

The environment variable DERIVEPATH can be used to declare a list of directories which contain the modules and/or interfaces that define the additional classes you wish to derive from. DrIFT is quite fussy about the format of the DERIVEPATH variable. The directory list should have the following format:

* each path should be separated by :

* no space inserted anywhere

* no final / on the end of a path

Examples of DERIVEPATH settings:

good - /users/grad/nww/share/hugs/lib:/users/grad/nww/share/hugs/lib/hugs

bad - /users/grad/nww/share/hugs/lib/:/users/grad/nww/share/hugs/lib/hugs/

© 2002 2004 DrIFT contributors

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

drift-ghc(1), ghc(1),

This manual page was written by Arjan Oosting <arjanoosting@home.nl> for the Debian system (but may be used by others).